FWIW, these socket tests were never 100% reliable on CPython 2.7 in the past. But I haven't looked at CPython 2.7 builds recently to see if this still holds. In any event, more work has been done in CPython 3.x to improve test reliability from a build bot perspective.
So given all of this: probably best to exclude and run manually until more investigation can be done. But it might be more worthwhile to do this work in Jython 3.x, and take advantage of the better testing done in CPython's network stdlib.